1. Field
Embodiments of the present disclosure relate to pre-impregnated fibers and, in particular, to methods for the fabrication of perforated prepregs, perforated prepreg layups, and composite structures.
2. Description of the Related Art
Fiber reinforced composites (FRCs) are hybrid structural materials that comprise a matrix component surrounding at least a portion of a fiber reinforcement that is configured in one or more layers. Owing to their relatively high stiffness to weight ratio, as well as their relatively low density, FRCs have found utility in applications, such as aircraft components, where weight is a significant concern.
FRC components may be manufactured using fibers that are pre-impregnated with the matrix component, also known as prepregs. To form a composite part from the prepregs, one or more layers of prepregs are assembled within a mold and heat may be applied to cause the matrix resin to flow, enabling consolidation of the prepreg layers. The applied heat may additionally cure or polymerize the matrix components.
The consolidation of prepregs to form composites in this manner is difficult, however. Gases may be trapped inside the prepreg and between the prepregs during layup and may also evolve during heating and/or curing of the prepregs. These gases are difficult to remove from the layup, as the matrix substantially inhibits movement of the gases and may result in porosity within the composite. This porosity can further reduce the mechanical properties of the composite.
Techniques have been developed to enhance removal of entrapped gases during composite fabrication, however, problems remain. For example, edge breathers may be employed to apply vacuum to the edge of prepregs in order to draw out gases from the sides of prepreg layers. However, removal of trapped gases from prepregs in this manner is slow and may not provide substantially complete removal of the trapped gases.